ORLANDO — The birth date for Marcus Smart reads 3/6/94 on the Celtics roster at the Orlando Summer Pro League. He is only 20 and a fresh-faced NBA rookie, just like the slew of players here born during the Clinton Administration.

There is a newness about each player here, first-year guys who are being exposed to NBA basketball for the first time. Dozens of scouts are here watching games, determining personalities and habits, scribbling notes down to create comprehensive reports.

Smart doesn’t need such attention. There is already a book on him. That was established during his career at Oklahoma State, a two-year stint that seemed to be 20 years considering his experiences, the most publicized a confrontation with a Texas Tech fan Feb. 8 in Lubbock, Texas.

A Red Raiders booster said something to Smart as he chased a ball out of bounds and landed near some seats. Smart rose and pushed the fan, prompting a five-game suspension from the Big 12. It was one of the biggest stories of the college basketball season and an indication it was time for Smart to head to the NBA.

Fast forward to Monday and the Celtics are being lambasted by the Indiana Pacers in a summer league game, Boston outscored, 65-21, in one stretch and the Pacers sensing weakness. Dee Bost, an NBADL veteran from Mississippi State, began jawing with Smart before an inbounds pass and Smart responded.

Officials told both to calm down and a Pacer yelled from the bench “He’s frustrated, man!”

The Celtics were trailing, 79-57, and Smart again had a tough game from the field. But Smart maintained his cool and responded with a 3-pointer, fully understanding this won’t be the first time an opposing player tries to test him.

Smart showed restraint and he also realizes that incident at Texas Tech will be something that he’ll have to deal with in his career.

“I definitely expect that,” Smart said. “I felt I reacted very well to that situation. I knew it was coming. You could hear it. I heard it. I didn’t let it bother me, I just blocked it out.”

While only Smart and Texas Tech booster Jeff Orr know what words were exchanged that night in Lubbock, the rest of the basketball community took notice. They know Smart does have a boiling point. They know that he has a history — albeit including one magnified incident — of snapping during difficult circumstances.

In a league in which everyone is considered possibly vulnerable and mental prey, Smart unfortunately will be subjected to on-court verbal attacks. His patience will be challenged. He will have to clench his fists, take a deep breath, and respond with his play and eventually the verbal attacks will cease. But that could take years.

“Definitely as a player, [the Texas Tech incident] is going to stick with me for a long time,” Smart said.

“The rest of my life, wherever I go, whoever I play, that’s what they’re going to know me as. But you know, that was an incident that happened. That’s not who I really am. Those teams trying [to get into my head], it doesn’t really faze me. I learned from my mistakes. I learned from that.”

The adjustment to the NBA is as much mental for rookies as it is physical. As one NBA rookie said, flabbergasted after a physical summer league struggle, “It’s a man’s game and I have to learn that.”

The mentally weak usually perish in the NBA and it’s an underlying part of the game. Kevin Garnett consistently would break down opponents with unrelenting trash talk, and they were so concerned about snapping back, they lost concentration, which Garnett relished.

Smart’s representatives knew their client carried that Texas Tech burden into the draft process and dedicated time to learning his persona.

“He’s the sixth pick of the Boston Celtics playing in summer league; people are going to come at you regardless,” agent Lee Melchionni said. “Because of that incident, people are going to want to see how he’s going to react. Marcus knows that and it’s basketball and it’s about competition. I don’t think he has an issue with it.”

The Celtics have been impressed with Smart’s demeanor, and his mother Camellia said her son called her shortly after the incident and admitted he was wrong.

“Marcus is a humble kid; his parents did a great job,” Melchionni said. “He realizes that he hasn’t made it. This is just the beginning and it’s about the work you put in from this point forward.”

Smart is wise beyond his years. He understands some are waiting for him to snap again, to express his frustration in a negative way. He said they won’t get that satisfaction.

“Of course teams are going to try me. I expect that,” he said. “I’m a good player, so I expect people to try to get me out of my game so it helps them. It’s a great tactic, but like I said, it doesn’t really faze me.”

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